1. Technical Field
The present invention generally relates to the art of connecting computers and specifically to a method of interconnecting at least two server computers, generally pertaining to differing corporate entities; each server being connected with a least one client computer and including, or having access to, a workflow control application.
2. Prior Art
Workflow control means and applications are well known in the art and operate with different media. Typical electronic workflow control applications (also termed Workflow Management System or WfMSs) are available commercially in various types and from various sources, e.g. in the form of specialized systems, such as “MQ Series Workflow®” from IBM or “TeamFlow®” from ICL, or as parts of so-called Enterprise Resource Planning Systems, such as R3® by SAP and Baan® by the Baan Company.
Today's systems of this type do not distinguish between and external view of a process that is visible outside the organization and its internal details. Their interfaces are generally aimed at the internal user. This is a problem if one organization (provider corporation) wants to perform a process on behalf of another (requestor corporation) so that it can be initiated and accessed by the requestor corporation through an automated interface and, vice versa, so that results generated by the provider can be reported back to the requestor.
This issue gains importance; specifically, an increasing need to outsource non-core business leads to increased service activity between separate companies. However, business organizations do not normally want to make internal information available to business partners nor do they wish to restrict their ability to conduct business internally. If separate organizations enter into a business relation, they will normally conclude an agreement or contract defining the circumstances under which the requestor corporation might initiate a process in the provider corporation and exchange further information when performing the process. As used herein, the term “contract” is a description of mutual obligations in the form of a protocol.
The use of server computers running a workflow control application in one and the same organization has been an issue for some time. Organizations want to deploy more than one server to balance workloads or to provide service at different sites that are connected by low bandwidth or only intermittently. If several servers are used, process templates have to be distributed as well as states and data of processes and activities. The various distributed parts have to be kept consistent. This problem has been discussed and described in the art; some solutions have been implemented in commercial products, such as IBM's MQ Series Workflow® mentioned above.
For the purpose of this specification, the terms “server” and “server computer” are used synonymously and refer to an electronic computer which functions as a “host” computer and is capable of being operatively connected with one or more “clients” (short for “client computer”). The connection of a server and at least one client results in a “net” (short for interconnected electronic computers).
A related issue is interoperability between workflow control applications of different vendors. Grown computer infrastructures tend to be heterogenous. This is a problem of providing standard interfaces to workflow control applications for server-to-server communication. Various attempts have been made at defining such an interface, e.g. by the ‘Workflow Management Coalition’, (a consortium of workflow control application vendors and users) which has created an interface called Interface 4 (cf. Technical Report WfMC-TC-1013, edited by the Workflow Management Coalition (1995), Hampshire, England The term “interface” is used to refer to a physical or virtual means capable of causing operative interconnection connection of physical and/or virtual entities.
These known interfaces help to cross vendor boundaries but do not cross corporate limits. Notably, such issues as privacy, flexibility and independence are not addressed because the relationship between internal (i.e. inter-corporate) and external (i.e. intra-corporate) interfaces is not a subject of such interfaces.
Another prior art attempt, i.e. the ‘Wide Area Groupflow’ system (cf. Nastanski et al; “Managing business process in virtual enterprises—interaction of distributed workflow mangament systems”; Proceedings of the ESTIEM, IT-Vision Conference, Paderborn (1997); and Riempp, G., et al, “Workflow management between distributed organizations—the wide area groupflow approach”, in Lehner et. Al (ed.) Proceedings of the ESTIEM, IT-Vision Conference; Deutscher Universitätsverlag, Wiesbaden 1997) suggests to connect processes across organizational boundaries. While this approach addresses the issue of privacy, it requires that the organizations declare process templates as externably accessible. As a consequence, this approach does not provide a means to map an external representation of a process to an internal one, which implies a loss of independence and flexibility.
Agreements and contracts are known per se in various fields of transactions, workflow management, and distributed systems in general: A first prior art contract approach (cf. Wächter, H. Et al; “The ConTract Model”, in Elmagarmid, A. K. (ed.) Database Transaction Models for Advanced Applications, San Mateo 1991) enables a performance of long-lived transactions of the type that can be perceived as processes, by committing, at an early stage, those parts of a transaction for which compensation mechanisms have been agreed upon.
Another prior art system termed “Coyote Approach” provides similar mechanisms while explicitly taking into account that services as parts of transactions can be executed in different organizations (cf. Dan, A. et al, “The Coyote Approach for Network—centric Service Applications; Proceedings of the Workshop on High Performance Transaction Processing HPTP, Asilomar 1997). The external services contemplated in this approach are short-lived, however. Similar properties are provided by the more recent TOWEC Approach (Verharen, E. M. et al, “Introducing contracting in distributing transactional workflow” in Proceedings of the 31st Annual Hawai International Conference on System Science, New York 1998); it allows closing contracts for process-type transaction steps rated ‘very important’.